A subscriber identity module (SIM) refers to a circuit that stores an International Mobile Subscriber Identity (IMSI). The SIM may securely store the IMSI and a key used to identify and authenticate a subscriber of a device accessing a mobile network. Typically, the SIM is a card that can be inserted into a device, such as a mobile phone or computer. As such, a device can be configured to operate with any given SIM, and the installed SIM uniquely identities that that user associated with the SIM is authorized to access the mobile network.